High strength inorganic cement compositions



United States Patent Oflice 3,365,319 HIGH STRENGTH INORGANIC CEMENT COMPOSITIONS Michael 1. Link, Nitro, W. Va., usignor to Union Carbide Corporation, a corporation of New York No Drawing. Filed Nov. 5, 1964, Ser. No. 409,307 8 Claims. (Cl. 106-90) ABSTRACT OF THE DISCLOSURE This invention relates to inorganic cement compositions of improved properties. More particularly, this invention relates to the addition of minor amounts of glyoxal to inorganic cement compositions whereby the compressive strength is substantially increased and other important physical properties markedly improved. comprehended within the broad scope of the invention are neat cements, mortars and concretes having minor amounts of glyoxal incorporated therein.

Many materials, both organic and inorganic in nature, have been utilized as admixtures in inorganic cement compositions to modify one or more of the properties of the cement. Thus, for example, aliphatic alcohols have been added to retard the setting rate, calcium lignosulfate has been employed to increase the cohesive and compressive strength, and sodium silicate has been utilized as a surface hardener. Latexes such as those based on butadienestyrene and vinyl acetate polymers have also found widespread application as admixtures because of their ability to increase the strength and abrasion resistance of cement compositions. However, certain disadvantages occur with the use of many of the admixtures heretofore proposed for incorporation in cementitious systems. Thus, in genera], a particular admixture will etiect improvement ;-in only a single property or frequently it is a material which is many times more costly than the cement itself and yet must be utilized in relatively large proportions, such as up to about 20 percent or more of the weight of the cement, to be effective.

It is a general object of this invention to provide inorganic cement compositions of improved properties. A more specific object is to provide inorganic cement compositions of increased tensile and compressive strength. Another object is to provide a method of reducing the water of workability required in inorganic cement compositions. A further object is to provide a method of controlling the time of set of inorganic cement compositions. Yet another object of the invention is to provide an admixture for inorganic cement compositions which is effective in modifying the properties of these compositions when employed in very small amounts. Other objects and advantages of this invention will become apparent to one skilled in the art in light of the disclosure which follows.

It has now been found that the addition of small amounts of glyoxal (O=CHCH=O) to inorganic cement compositions results in remarkable improvement in the properties thereof and, accordingly, the present invention includes within its scope all cement compositions comprising an inorganic cement and a strength improving amount of glyoxal. The amount of glyoxal required to effect the maximum improvement in the properties of an inorganic cement composition is dependent to some ex- 3,365,319 Patented Jan. 23, 1968 tent on the type of cement and on the other components present in the composition but the optimum amount in a particular instance can be readily determined by routine experimentation. Most usually, amounts of from about 0.01 percent by weight of glyoxal, based on the dry weight of inorganic cement, to about 2 percent by weight, or more, are employed, while preferred amounts are from about 0.05 percent to about 1 percent.

The improved inorganic cement compositions of this invention exhibit a unique combination of desirable prop erties. Compressive strengths have been found to be creased by as much as 50 percent, or more, compared to that of the same cement composition without the benefit of the added glyoxal, while, in addition, a moderate in crease in tensile strength is often etlected. A particularly important benefit of the addition of glyoxal to inorganic cement compositions in accordance with the method of this invention is the resulting reduction in the water of workability required. As is well known, the stoichiomeiric amount of water required for reaction with the cement is almost always insutlicient to permit preparation of a slurry that can be conveniently handled so additional water, termed "water of workability, is normally added. The water of workability adversely changes almost every desired property of the hardened cement product and it is therefore important to keep the amount of such water to a minimum. By the addition of glyoxal in the amounts specified herein, the required water of workability is often reduced by as much as 10 to 15 percent or more. Effective control of the time to initial set may also be achieved by the incorporation of minor amounts of glyoxal in an inorganic cement composition.

The degree of improvement in the compressive strength of inorganic cement compositions resulting from addition of filyoxal thereto in accordance with this invention gen eral y increases, to a degree, with increasing concentration of the glyoxal. However, the initial time of set is increased by the addition of low concentration of glyoxal, such as amounts of less than about 1 weight percent, but decreased by higher concentrations and thus passes through a maximum as the concentration of glyoxal is varied.

The present invention is applicable to all cementitious systems comprising an inorganic cement. For example, glyoxal can be successfully employed to improve the properties of grouts (cement-water mixtures) and mortars (compositions containing sand, cement and water) as well as concretes (compositions containing aggregate such as gravel, crushed stone, etc. along with sand, cement and water). The term inorganic cement as employed herein and in the appended claims is intended to include the by draulic cements, the lime cements, the gypsum cements, and the plaster cements. Of these the hydraulic cements are of particular importance and, accordingly, serve as components of a preferred class of inorganic cement compositions within the broad scope of this invention. The term hydraulic cement" is recognized in the art as defining a definite class and it is intended to cover all members of such class by the claims appended hereto. Hydraulic cements include, but are not limited to, the Portland cements, the natural cements, the white cements, the aluminous cements, the grappier cements, the hydraulic limes, and the puzzolanic cements including those derived from industrial slags. The hydrauliccement which is most widely used, because of its amenability to low cost pro duction, is Portland cement, and Portland cement com-- positions containing small amounts of glyoxal are particularly preferred compositions within the scope of this invention.

Glyoxal may be incorporated in inorganic cement compositions in accordance with this invention in any suitable manner. Thus, the glyoxal may be dissolved in the water employed in formulating the cement composition or may be employed in a spray dried form and dry blended with the cement during one of the conventional steps in cement manufacture, for example, during the finish grinding 4 (l) The mixer was buttered" with a size batch. (2) The butter batch" was discarded. (3) Three-fourths of the anticipated water requirement was charged to the mixer.

operation. In preparing concrete, the glyoxal may be used (4) All of the sand and stone was charged to the mixer in admixture with the dry cement or admixed with any (with the percent moisture contents on each being deone of the other components of the concrete prior to the termined subsequently by oven drying of samples). incorporation of the dry cement. Glyoxal is available (5) The mixer was operated for 15 seconds. commercially as a 40 percent aqueous solution which con- 6) All of the cement was charged to the mixer.

tains small amounts of ethylene glycol, glycolic acid, (7) The mixer was operated for a two minute period formic acid and formaldehyde and such commercial maduring which additional water was added in an amount terial is fully satisfactory for the purposes of this invensufl'icient to give a 331% inch slump.

tion and can be added to the water used in formulating (8) The mix was permitted to stand for a two minute the cement composition. period.

The improved inorganic Infill Compositions of this (9) The mixer was operated for two minutes.

invention find application wherever cement compositions (10) Mixing was stopped and tests run for slump, are ordinarily used but are particularly applicable in uses ai o t t d it i ht, wherein very high ultimate compressive strength is essen- 11) Th t t d t ri l f t (10) was rammed tial or when rapid development of strength is important. to the ix d f-mixcd Arm of application where the enhanced properties (12 The entire batch was discharged into a metal closed hflein Particularly striking advamaggs are, tub and specimens for the proposed tests were cast. After for example, in the construction of high rise buildings and casting all specimens were aged at and the preparation of prestressed concrete. relative humidity.

Further illustration of the invention is provided by the examples which follow. In the examples, the mixing pro- Example I cedure set forth in detail below was utilized in all cases and evaluation of the cement compositions was made in accordance with accepted test procedures of the ASTM genes or confide wmauimg (American Society for Testing Materials), which are traumas glyoxal were Pf accordano? with listed below along with a description of any modification the "mung l descnbm above and of f the standard test proccdm-e sorted to i b i i set and compressive strengths determined. The test data the data are summarized for convenience in Table I below with SIump.-Deterrnined by ASI M C 143-58. the quantities of material given being on the basis of One Air c0ntem.-Determined by ASTM C 231-60. cubic yard of concrete.

TABLE I Time of set Compressive Strength (p.s.i.) Test Cement Band Stone tllz'oxal Unit (hrs) No. (lbs) Obs.) (lbs) wt. w/c Percent Air Waifht percent) (lbs. it!) Initial Final 7 days 14 days %days bfidays 1-5- 504 1,330 1,430 0 0.54 2.4 145.2 4.5 05 3,500 4,200 4,530 4,070 1-B 504 1,330 1,430 0.035 0.40 20 man 40 as 4,000 4,550 4,030 1-0.-." 504 1,330 1,430 0.07 0.51 20 1420 51 as 4,250 4,7s0 5,520 5,820 1D 504 1,330 1,430 0.10 0.45 2.1 143.4 4.8 03 4,000 5,250 0,300 0,000

1 Type I, Lehigh Portland Cement Company, t Values reported are lor 100% glyoxal and are based on the weight 01 I 3.30 RM. (fineness modulus) River Sand. dry cement. I M.S.A. (maximum size aggregate) River Gravel. Water to cement ratio for a slump of 3:54.

Time of .reI.-Dctermincd by ASTM C 403-61 T ex- Consideration of the above results indicates that the cept that the mortar containers employed were 4" x 4" addition of glyoxal brings about a substantial increase in x 16" molds of thick plywood that had been coated the compressive strength of the concrete and a substanwith paraffin to act as a release agent and to prevent loss tial reduction in the total water required. For example, of water to the mold. the addition of 0.10 percent glyoxal, based on the dry Compressive strenglh.--Deterrnined by ASTM C 39- weight of cement, resulted in an increase in the 28-day 61. Test specimens were prepared in accordance with compressive strength of almost 40 percent and a reducthe method described in ASTM C 192-59, the cylindrition in the total water required of about 17 percent. cal specimens being 4 inches in diameter by 8 inches in Example 2 length and the maximum size aggregate being nominal size. Two concrete mixes, one a conventional mix and the Tensile slrenglh.Determined by ASTM c 496-62 T. ther con i i g a small amount of y were p Volume change.--Determined by ASTM C 157-60 T. pared in accordance with the mixing procedure described Mixing procedure.Concrete samples evaluated herein above and both the compressive and tensile strengths were were prepared in accordance with the following schedule determined. The test data are summarized for convenience of steps. In each instance where glyoxal was utilized, it in Table II below with the quantities of material given was added to the water charged in step (3). being on the basis of one cubic yard of concrete.

TABLE 11 Compressive Strength (p.s.i.) l 8 nd Stone Glyoxal W/C' Percent a ight mi;

'iiiigii (ins) (lbs) (wt. percent) Air (tbs/i gegfi 1! g (1:75 ig g days 3:31.; a is 33 33 3:2 13;: :33 as as is 332 33 Q 1 Type I, Lehigh Portland Cement Company.

1 2.30 FM. (fineness modulus) River Sand. 1 $4 M.S.A. (maximum size aggregrate) Indiana Lime tone.

Values reported are (or glyoxal and are based on the weight 01 dry cement.

# Water to cement ratio 101' aslump 013116.

Consideration of the above results indicates that the addition of glyoxal results in a substantial increase in the compressive strength of the concrete regardless of the aging period to which the specimen is subjected. Thus, the

l. A cement composition consisting essentially of Port land cement and a strength improving amount of glyoxal 2. A cement composition comprising Portland cement and from .about 0.01 to about 2 percent by weight of addition of 0.15 percent glyoxal, based on the dry weight 5 glyoxal based on the dry weight of the Portland cement. of cement, resulted in a 41 percent increase in 7-day A men! composition comprising Portland ccmem strength, a 52 percent increase in 28-day strength, and a and from about t0 {bout 1 Pcwefli y Wight 0f 8 38 percent increase in ISO-day strength. The 28-day tenon! on f of the Portland sile strength was increased about 12 percent by addition Commie compnsmg Portland and aggmgm 0H) 15 weightpememglyoxfl l0 and from about 0.01 to about 2 percent by weight of glyoxal based on the dry weight of the Portland cement Example 3 5. A method of improving the physical properties oi 1 a Portland cement composition which consists essentially A third of meme vanous 9" of incorporating in said composition a strength improving centrations of glyoxal were prepared in accordance with 15 amount of glyoxal mmng procedfrc descnbed above and the compres' 6. A method of improving the physical properties of a strength and of set f reForded' The Portland cement composition which comprises incorporat' test data are summarized for convenience 1n Table I1] ing in said composition f about ()1 to about 2 below with the quantities of material given being on the nt by weight, based on the dry weight of the Portland basis of one cubic yard of concrete. cement, of glyoxal.

TABLE 111 Test Cement [Sand Stone Glyoxal Unit i l h s i i gii No. (lbs) tlbs.) (lbs) (wt. percent) W/C Percent Air lWeight 250 p s 1 Initial Final Idaysgl4daysi28dayst5orinys 504 1,450 1,430 0 0.57 2.0 142.0 5.4 4,710 saaoimau 0,400 504 1,450 1,430 0.05 0.x 18 141.2 0.3 7:10 5,520 I 0,020 0,050 504 1,450 1,4110 0.1 0.53 2.3 140.11 5,2a0 5,000 0,550 0,050 504 1,450 1,430 0.2 045 2.1 140.4 7 0,230 6,650 7,200 7,880 504 1,450 1,430 0.4 0.48 2.0 140.0 0,000 7,450 7,000 8,050 554 1,450 1,430 0.0 0.49 21 141.2 0,400 7,000 0,050 8,970 504 1,450 1,430 1.0 0.40 3.4 141.0 5,950 7,300 7,000 asst:

I Tgbpe I, Lehigh Portland Cement Company. Water to cement ratio for a slump of 31:51 I 3. F M. (fineness modulus) River Band, Time to reach a penetration resistance 01 250 p.s.i I y" MBA. (maximum size aggregate) River Gravelv 7 Values reported are an average of iour separate tests. Values reported are for 100% g yoxal and are based on the weight 01 I 1w p,g,i pgnetrgflon resi tanc at 6.5 hours. dry cement 128 psi. penetration resistance at 6.0 hours Consideration of the above results indicates that the 7. A method of improving the physical pr perti s f addition of glyoxal substantially increases the compres at Portland cement composition which comprises incorposive strength of concrete and that increasing the concen- 40 rating in said composition from about 0.05 to about 1 "anon 8W "P w about 1 P based on the percent by weight, based on the dry weight of Portland dry weight of cement, results in an increase in the time cement, of l l, of set, i.e. the setting of the concrete is retarded. g A method of improving the h i l propcnies f Example 4 concrete comprising Portland cement and aggregate which comprises incorporating therein from about 0.05 to about A concrete mix identical to those described in Example 3 above was prepared except that the amount of glyoxal i g igi g 2 81y oxal based on the dry welgm added was sufiicient to give a concentration of 3.0 pere n cent, based on the weight of dry cement. As a result of R f C d the high concentration of glyoxal the concrete set sube 8 slantially instantaneously, i.e. flash set. This test indicates that high concentrations of glyoxal bring about a reversal in the effect on time of set resulting from addition of low concentrations, such as concentrations of less than about 1 weight percent, and in fact can greatly accelerate the 50 setting of the concrete. Effective control over the time of set can thus be achieved by varying the amount of glyoxal incorporated in an inorganic cement composition in accordance with the method of this invention,

What is claimed is;

UNITED STATES PATENTS 2,225,146 12/ 1940 Bechtold lO6-90 3,028,340 4/1962 Gandon et a] 106-74 3,144,347 \8/ 1964 Cowan 106-90 3,216,966 11/1965 Collins et al l06-90 TOBIAS E. LEVOW, Primary Examiner, S. E. MQ'IT, Assistant Examiner, 

